The present invention relates in general to braking apparatus and, more particularly, the invention relates to a brake apparatus for retarding relative movement between two members in which at least one of the members is movable and/or turnable axially and which brake apparatus has relatively few parts which move relative to one another.
Such a brake and/or clamping mechanism, for example, can be utilized to brake and lock a piston rod connected to a working piston of a working cylinder and may be actuated by a fluid pressure medium. A working cylinder equipped with such a mechanism may have numerous uses such as, among other things, it is applicable in a window and ventilator actuation arrangement.
Prior to this invention, it was known to provide a brake apparatus with a clamping mechanism which included a first casing encasing the piston rod and a second casing arranged coaxially therewith. In the first casing, radially arranged clearances were provided to receive the clamping elements. On the sides of the clamping elements, which were facing the second casing, bearings were arranged to receive roller bodies which rest against a roller path arranged on the second casing and running diagonally to the longitudinal axis of the piston rod. Therefore, with a shifting movement of the second casing relative to the first casing, the clamping elements may be pushed against the piston rod--depending on the direction of movement with respect to the second casing--so that the piston rod is locked or restrained.
A disadvantage with regard to the clamping mechanism described above is the fact that several parts which are movable relative to each other are required. Therefore, they must be fabricated with great care to ensure very precise fits in order to assure good operating function even under extreme conditions. Evidence of wear frequently appears which is caused by the friction between the individual parts. Examples of such wear may be found between the brake element and the guide for the brake element; the roll body and the roll body bearing in the brake element.